Beaverton, OR planting zone & frost dates

Beaverton is in USDA hardiness zone 9a. The last spring frost usually comes around February 11 and the first fall frost around December 5, for a growing season of about 303 days.

USDA hardiness zone9aavg. extreme winter low 20°F to 25°F
Average last spring frostFebruary 1190% chance of no frost after March 5
Average first fall frostDecember 510% chance of frost by November 11
Growing season303 daysfrost-free days in an average year

Planting calendar for Beaverton

Dates are counted from the average last spring frost (February 11) using the typical timing recommended by U.S. extension services. Warm-season crops go out only after the danger of frost has passed and the soil has warmed.

CropWhen
TomatoesStart seeds indoors: Dec 17 – Dec 31
Transplant outdoors: Feb 18 – Feb 25
PeppersStart seeds indoors: Dec 3 – Dec 17
Transplant outdoors: Feb 25 – Mar 4
EggplantStart seeds indoors: Dec 3 – Dec 17
Transplant outdoors: Feb 25 – Mar 4
BroccoliStart seeds indoors: Dec 3 – Dec 17
Transplant outdoors: Jan 14 – Jan 28
CabbageStart seeds indoors: Dec 3 – Dec 17
Transplant outdoors: Jan 14 – Jan 28
Onions (sets)Plant outdoors: Jan 14 – Jan 28
PeasSow outdoors: Dec 31 – Jan 14
SpinachSow outdoors: Dec 31 – Jan 14
LettuceSow outdoors: Jan 14 – Jan 28
CarrotsSow outdoors: Jan 14 – Jan 28
PotatoesPlant outdoors: Jan 14 – Jan 28
BeansSow outdoors: Feb 18 – Feb 25
Sweet cornSow outdoors: Feb 18 – Feb 25
CucumbersSow outdoors: Feb 18 – Feb 25
Squash & zucchiniSow outdoors: Feb 18 – Feb 25
BasilStart seeds indoors: Dec 31 – Jan 14
Transplant outdoors: Feb 18 – Feb 25

Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Oct 10 (8 weeks before the average first fall frost on Dec 5).

Useful for zone 9a gardens

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Frost risk in detail

90% chance50% chance10% chance
Last 32°F frost in spring is afterDec 26Feb 11Mar 5
First 32°F frost in fall is beforeJan 12Dec 5Nov 11

How to read it: in spring there is a 10% chance of a frost after March 5, so that is a safe date for tender plants. In fall there is a 10% chance of frost before November 11. A hard freeze (28°F) usually ends around January 6.

Hardiness zone by ZIP code in Beaverton

Nearby cities

All cities in Oregon → · Other zone 9a cities →

Questions

What growing zone is Beaverton, OR?

Beaverton is in USDA Plant Hardiness Zone 9a (average extreme winter low 20°F to 25°F), according to the USDA 2023 map. Some ZIP codes of the city fall in zone 8b.

When is the last frost in Beaverton?

The average last spring frost (32°F) in Beaverton is February 11. There is still a 10% chance of frost until March 5.

When can I plant tomatoes in Beaverton?

Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Feb 18 – Feb 25. Start seeds indoors 6–8 weeks before the last frost.

Frost dates: NOAA U.S. Climate Normals 1991–2020, station Nature Park-Beaverton, OR (USC00355945), 3.0 km (1.9 mi) from the city center, elevation 56 m, based on 12 years of records. Hardiness zone: USDA Plant Hardiness Zone Map 2023 for the ZIP code nearest to the city center. Microclimates (valleys, hills, cities, coasts) can be warmer or colder: check the local forecast before planting. How we calculate the data.